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Posted

What would a space craft look like while moving if the following was true.

 

If a space ship could travel by making small jumps of say one meter. These jumps would take zero time, this is inspired to some extent by quantum tunneling, if the space craft could make 10 to the 16th power jumps per second it would be traveling quite a bit faster than light but what would it look like to an outside observer? Since the space craft would never actually be traveling faster than light between jumps how would it appear in motion to an observer at say 10 to the third power jumps 10 to the forth and so on. Would it appear to just be moving fast or would it become invisible at some point? My own take is that it would appear to be moving very fast but still be able to be seen. If you were far away it would just appear to be going slow like a jet plane looks when it is miles away but traveling at Mach two.

Posted

If you were able to set up a really high speed camera, I think it would capture the jumps as a series of stationary images of the ship. To the human eye, however, I would think that it would be seen as a continuous motion (iow, you wouldn't see the jumps).

 

Length contraction is something to consider though:

 

[math]L'=L\sqrt{1-v^2}/c^2[/math]

Let's assume the ship is 10m long at rest.

[math]L'=10m\sqrt{1-10^{32}m/s}/9e16[/math]

Fudging the numbers so that c^2 is 10e16 (to make the math easier) we get:

[math]L'=10m\sqrt-9e15[/math]

I'll stop there because the number is going to be imaginary. But, for the purpose of this question, the ship would have negative length. So, it would not be visible at all.

 

Can someone check me on this?

Posted
If the ship was stationary between jumps, and only seemed to move because of the jumps would it still appear to be negative ?

 

It would only be negative when moving (I'm assuming infinite acceleration/deceleration).

So, it would appear only when stationary. Though, I'm not too sure how negative length contraction would affect the integrity of the ship. You might not see it after it makes that first jump. :)

Posted
Since the idea is quantum tunneling of a large object i have to ask do electrons have a negative length when they tunnel?

 

My understanding of quantum tunneling is that it is not transmission of information at faster than light speed, so no it wouldn't have negative contraction. Also, tunneling can only occur in the quantum domain. It wouldn't be possible to quantum tunnel a ship.

Posted

I think the question is, for whom are these jumps taking no time? Is it for the person observing them or is it for the person jumping.

 

To instantly jump from one spot to another from your own perspective, you would travel at the speed of light. For an observer to see something instantly jump from one place to another, it would have to move backwards on a spacetime diagram (backwards in time).

 

~modest

Posted
My understanding of quantum tunneling is that it is not transmission of information at faster than light speed, so no it wouldn't have negative contraction. Also, tunneling can only occur in the quantum domain. It wouldn't be possible to quantum tunnel a ship.

 

Oh I know it can't be done any more than i can accelerate faster than light but we do know what it would look like if we did go faster than light, negative length is just a small part of it but if we could quantum tunnel a large object what would they effect be as the object jumped one meter many times a second. enough times a second 300,000 times and it would be traveling at light speed but not moving in real space. How would it appear to an outside observer, would it be like a florescent light, the flicker would be too quick to notice so it would just appear to move fast or would the appearance and disappearance distort the view of the ship to an outside observer?

Posted
I think the question is, for whom are these jumps taking no time? Is it for the person observing them or is it for the person jumping.

 

To instantly jump from one spot to another from your own perspective, you would travel at the speed of light. For an observer to see something instantly jump from one place to another, it would have to move backwards on a spacetime diagram (backwards in time).

 

~modest

 

 

I think I understand what you are saying but the ship would be stationary between jumps and nonexistent in real space during a jump. Lets say for the sake of argument the ship only jumps 1000 times a second, in one meter jumps, what would it look like then? would it appear to move smoothly at 1000 meters a second?

 

BTW, i accidentally put another misspelled word in my spelling dictionary, anyone know how to remove it?

Posted

I think it's useful for this problem to think of the stationary moments of the ship as frames (like video). So in this case, the ship would be moving at 1,000 frames per second. Since modern movies run at 24 fps, it's pretty safe to assume that someone watching the ship would see a continuous motion.

 

Source: Persistence of vision - Wikipedia, the free encyclopedia

 

Edit: Here's another good wiki page related to this:

Flicker fusion threshold - Wikipedia, the free encyclopedia

Posted
Can this be extrapolated to 1,000,000 jumps a second or more? Or would something different happen when you went past 300,000 jumps a second?

 

It would be the same for 1,000,000. Did you mean to type 300,000,000 (speed of light)?

Posted
It would be the same for 1,000,000. Did you mean to type 300,000,000 (speed of light)?

 

I thought the speed of light was 300,000 meters a second, but if it is 300,000,000 meters a second then that's what i meant.

Posted
I think I understand what you are saying but the ship would be stationary between jumps and nonexistent in real space during a jump.

 

Ok, if these jumps are not happening in spacetime (in other words, it's not moving from one place to the other) then, I guess, maybe... I'll throw this out there and let someone with a stronger grasp of physics shoot it down...

 

 

The example is slowed down. The ship jumps 6 of red's light-seconds then persists in reds frame of reference for 2 seconds, then jumps another 6 light seconds and persists for 2... and so on.

 

Red would see green disappear then reappear 6 light-seconds away. Red would then see green normally (normal rate of time, normal length, not redshifted) for 2 seconds after which green would disappear again. It reappears six seconds later, now 12 light-seconds away and appears normal for 2 seconds.

 

Green would presumably experience no time between jumps (although this seems somewhat arbitrary). After each jump, red will appear 6 seconds younger and 6 light-second more distant. Between jumps red would appear to move forward in time normally for 2 seconds (not redshifted or time dilated). Then another jump and red is again six seconds younger and 6 light-seconds more distant and moving forward in time normally for two seconds... and so on.

 

If this happen quickly enough, I suppose green would appear to move in slow-motion to red, and red would appear to move in fast-motion in reverse to green.

 

But, again, green is not following the laws of motion or SR between jumps in the above example, and everything I just said may be completely wrong. I'm uncertain.

 

... and I have no idea how to remove a word from the spelling dictionary.

 

~modest

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